The FM Transmitter 3 is a great way to deliver near-broadcast audio from any digital audio device to a traditional radio. Use the attached cable to connect to a headphone jack on your smart speaker, smartphone, or television to send near-broadcast quality audio to any nearby radio or stereo system. You can resolve audio delivery problems by using it with your iPhone, Alexa type device, WiFi internet radio, or satellite radio. Other customers have told us how they use it with their televisions, guitars, portable DVD players or iPod (a lot of fun in cars) and even other radios. We use it regularly for listening to training videos at our company meetings. It has a thumbwheel that allows you to adjust the input for perfect audio quality and a two-level LED indicator to help set optimal signal level. It broadcasts clean, very high-fidelity stereo audio. Maximum distance is about 45 feet line of sight with no obstructions. Broadcast distance will vary depending on your location. AC adapter included or runs on two "AA" batteries (not included). FCC compliant. Choose any FM frequency between 87.5 MHz and 108 MHz. Portable, fits in the palm of your hand. Weight: 5.8 oz. Size 3" W x 3.5" H x 1" D.